Wednesday, September 19, 2012

Fortress on the Bluff: Ingenuity and Innovation at the Twin Lights of NavesinkWritten by NJ Historian

Two hundred feet
above sea level on the New Jersey coast is a peculiar bluff with what looks
like a fortress resting atop. This “fortress” has been protecting and guiding
ships into New York Harbor for 150 years. The Twin Lights Lighthouse has been
home to a number of firsts in lighthouse history and wireless innovation
because of their unique and strategic location. The lighthouse was one of
America’s most technologically connected and continues to connect curious
visitors with the past 150 years later.

A lighthouse was
built on the bluff as early as 1828. The original Twin Lights were designed by
Connecticut architect Charles H. Smith. Smith was instructed to “well and
faithfully construct, erect, build, and in every respect completely finish two
lighthouses and a dwelling house...on the Highlands of Navesink.” The towers he
designed were approximately 40 feet tall. The original keepers’ quarters was constructed
of wood, with two rubble stone towers and beacons 320 feet apart. The first
light keeper was Joseph Doty of Somerville and was paid $40.00 a month in 1828.
The United States Lighthouse Board decided on two lighthouses in the Highlands
in order for mariners to distinguish them from the Sandy Hook Lighthouse, five
miles to the north. In the early 1800s, the U.S. Lighthouse Board philosophy
stated that lighthouses should have a fixed (non-rotating) light, thus
necessitating the two lights in the Highlands in order to avoid confusion with
Sandy Hook’s fixed light. Ultimately it was decided that one tower was to have
a fixed light and the other a rotating light. The U.S. Lighthouse Board
constructed seven dual or twin lights, and one triple light, following the same
philosophy. However, the high operating expense of these multiple units
eventually convinced the board to consider other alternatives. Finally, the
U.S. Lighthouse Board determined it would be more cost effective and practical
to give each lighthouse its own distinguishing light pattern.

1861 lithograph of the original north tower and construction of the new tower. Source: Twin Lights Archive.

In 1841, a pair
of Fresnel lenses was installed at the Twin Lights. The lenses were the first
ones brought to the United States. Three years earlier, Commodore Matthew Perry
was dispatched by Congress to study European lighthouses. During his time in
Europe he learned about the work of French physicist Augustine Fresnel. The
Fresnel lens was far superior to any navigational lighting apparatus being used
in the United States at that time. The lens used concentric rings of glass
prisms to concentrate ambient light into a narrow beam. The center of the lens
was shaped like a magnifying glass, so the concentrated beam was even more
powerful. Tests showed that while an open flame lost nearly 97% of its light,
and a flame with reflectors behind it still lost 83% of its light, the Fresnel
lens was able to capture all but 17% of its light. Because of its amazing
efficiency, a Fresnel lens could easily shine its light twenty or more miles to
the horizon. Fresnel produced six
sizes of lighthouse lenses, divided into ordersbased on their size and focal length.
In modern use, these are classified as first through sixth order. The Twin Lights’ lenses resembled huge bee hives of glass
surrounding a light. The lenses were capable of producing 6,000,000
candlepower. The south tower of the Twin Lights received a first-order lens and
the north tower received a second-order lens.

Original second-order lens from the north tower in the 1902 generator building.

By 1852, Congress
received a report on the nation’s lighthouses that was highly critical. The
Twin Lights, which at that time were in desperate need of repair were ironically
singled out as the best in the nation. The report said the towers, “are in a dilapidated
condition, the consequence of original bad materials and workmanship, and it
has been represented that there is apprehension they are not capable of
standing much longer.” Because of the report’s findings, the U.S. Lighthouse
Board was created. One of their first acts was ordering a rebuilding of the Navesink
Light Station.

In 1862, a new
Twin Lights Lighthouse was constructed at a cost of $74,000. It is the only
lighthouse in the United States built in a fortress style. It was designed by
architect Joseph Lederle of Staten Island and was constructed of brownstone, an
unusual feature as brownstone was chiefly used in residential building. The new
towers would be 250 feet apart and connected by a keeper’s dwelling. The north
tower was constructed in the shape of an octagon and the south tower was square,
giving them a unique appearance.

Schematics of the north tower. Source: National Archive.

In 1898, the original south tower lens was replaced with one of the largest bivalve lenses ever produced. In that same year the south tower was electrified with an electric arc lamp, the first time an American lighthouse was to be powered by electricity and have its own generating plant. It was the only on-shore lighthouse in the United States with its own generator. The electric arc light produced 25,000,000 candlepower and was the most powerful light installed in a lighthouse in the United States. Its light was visible for twenty-two miles at sea, though there were reports of it having been seen as far away as 70 miles when the light was reflected off a low lying cloud bank. That same year the light in the north tower was discontinued.

The south tower was automated in 1949 but was discontinued in 1952 as the importance of lighthouses diminished. In 1962, the site was turned over to the State of New Jersey, which installed a sixth order lens and reactivated the north tower as a private aid to navigation. The north tower remains active to this day.

The Twin Lights
are also associated with a number of other important events:

First
Official Reading of the Pledge of Allegiance

In 1893 the Twin
Lights were selected as the location for the first official reading of the Pledge
of Allegiance as America’s national oath of loyalty. This event coincided
with the opening of the Colombian Exposition in Chicago and featured a grand
naval flotilla off the coast of Sandy Hook. The Pledge of Allegiance event was
held around a new addition to the Twin Lights, a 135-foot Liberty Pole. During
the 1890s and early 1900s, the Liberty Pole was the first “piece of America”
seen by millions of immigrants as their ships travelled toward Ellis Island.

Wireless
Telegraph

Messages from
the first practical demonstration of wireless telegraph were sent from the site
on September 30, 1899 by famous Italian inventor Guglielmo Marconi. Marconi had
been invited to America by Gordon Bennett, Jr., the owner of the New York
Herald to report on the America’s Cup sailboat race using his wireless
technology. He transmitted messages from a boat offshore, which were then sent
to the newspaper for publication. Marconi maintained a wireless station at the
Twin Lights for a few years before deciding that other locations on the United
States’ coastline would provide better reception for his equipment. Marconi’s experiments
established the commercial viability of wireless communication and provided the
foundation for the technology that led to the wireless devices which are
commonplace today.

Marconi's radio antenna. Source: Twin Lights Archive.

Radar

Starting in the late 1920s, a series of top-secret
experiments took place at Fort Monmouth. In 1935, the U.S. military set up at
the Twin Lights to test what the newspapers were calling a "mystery ray."
Eventually
the “mystery” was solved and it is now called radar. The radar experiments held
at the Twin Lights helped the Allies win World War II and led directly to the
innovations that today guide airplanes and even missiles!

Over the past 184
years, the Twin Lights site has been host to a number of firsts and
technological achievements in the United States. From its first keeper, Joseph
Doty, to the last keeper, Murphy Rockett, these men and their families watched
experimentation, innovation, and progress occur right before their eyes, 200
feet above sea level in their fortress with a view of the ocean.